Technical Field
This invention generally relates to an image forming apparatus, such as a copier, a printer, a facsimile machine, and a multifunction peripheral (MFP) having at least two of coping, printing, facsimile transmission, plotting, and scanning capabilities.
Description of the Background Art
In image forming apparatuses, latent images formed on an image bearer such as a photoreceptor are developed with developer including at least toner. As toner is thus consumed in image development, toner is supplied by a toner replenishing device provided in the image forming apparatus. For example, JP-2012-133349-A proposes a configuration in which the toner replenishing device transports toner from a toner bottle to a developing device.
There are cylindrical toner bottles having a spiral protrusion protruding inward from an inner circumferential face thereof, and there are toner replenishing devices that include a temporary reservoir to temporarily store toner supplied from the toner bottle. Such a toner replenishing device further includes a first toner conveyance device to transport toner from the toner bottle to the temporary reservoir and a second conveyance device to transport toner from the temporary reservoir to the developing device. The first toner conveyance device is constructed of a bottle driving motor to rotate the toner bottle, the spiral protrusion formed in the inner circumferential face of the toner bottle, and the like.
In the state in which the toner bottle is mounted in the toner replenishing device, the toner bottle is rotated by driving force of the bottle driving motor. Then, toner is transported by the spiral protrusion to an opening formed in the toner bottle and supplied to the temporary reservoir.
The second conveyance device is constructed of a toner conveying screw, a driving motor to rotate the toner conveying screw, and the like. When the toner conveying screw is rotated by the driving motor, toner in the temporary reservoir is transported to an toner outlet and further to the developing device.
In such configurations including the temporary reservoir, even when almost all toner in the toner bottle is used up, toner can be supplied from the temporary reservoir to the developing device for a certain period, thus enabling printing operation.
Additionally, typically a toner amount detector is provided to an inner wall of the temporary reservoir to detect the presence of toner at a predetermined height (i.e., level), thereby detecting the amount of toner in the temporary reservoir. According to detection results generated by the toner amount detector, toner is supplied from the toner bottle to the temporary reservoir to keep the amount of toner in the temporary reservoir at a predetermined amount.